The new OS has a brand new interface, new processor support, massively improved touch features and a host of interesting new things, and it’s quite dramatically different from the Windows 7 we know and love.

It’s also very different from Apple’s OS X Lion, which introduced massively improved touch features and a host of interesting new things. So which one are you likely to prefer – Apple’s OS, or Microsoft’s? Would you be better off sticking with Windows 7? Let’s find out.

Windows 8 vs Windows 7 vs OS X Lion: hardware

These days OS X is a 64-bit Intel-only affair, while Windows 7 requires 32-bit or 64-bit Intel or AMD processors. Windows 8 adds ARM support to the mix, although ARM devices will need specially compiled applications.

Actual system requirements for each OS are reasonably low: Lion wants a Core 2 Duo or better with 2GB of RAM, while Windows 7 and 8 both want a 1GHZ processor with 1GB of RAM (2GB for 64-bit).

As ever, OS X is only officially supported on Apple kit while Windows is available on all kinds of hardware, and OS X is strictly a desktop OS. Windows 7 is technically a tablet OS too, while Windows 8 has been specifically designed with tablets and touch-screen PCs in mind.

EVERYTHING EVERYWHERE: Windows 8 is designed to run on everything: Intel laptops, AMD desktops, ARM tablets and anything else you can think of

Windows 8 vs Windows 7 vs OS X Lion: interface

The Windows 8 interface takes a bit of getting used to, as it’s a combination of the familiar Windows interface with a few big changes – especially on tablets. T

he Start menu’s gone, replaced by a Start screen that resembles the Windows Phone and Kinect interfaces, and programs will be able to run in full screen mode or tiled together in a split screen view. The traditional Windows desktop will be available too, and Windows Explorer will get an Office-style ribbon interface.

We like what we’ve seen of Windows 8 so far, but the interface is still in development so it’s too early to reach a firm conclusion on whether it works or not. There’s no doubt that it’s much nicer on tablets than Windows 7 is, though.

Lion is more of an evolutionary step: scrollbars have been squashed, the colour bleached out of the UI, the iOS-style LaunchPad app launcher added and a bloody horrible skin put on top of the otherwise excellent iCal, along with dozens of minor interface improvements. It’s essentially a more refined version of the Snow Leopard UI – or at least, it is until you use it with a trackpad. Then it becomes a very different beast.

SITTING PRETTY:We love the Metro user interface, but the classic Windows desktop is there to keep old hands happy

Windows 8 vs Windows 7 vs OS X Lion: touch

Windows 8, like Lion, is all about the fingers. Forget Windows 7′s faintly horrible touch features: Windows 8 is firmly finger-friendly, with a nice on-screen keyboard, gesture recognition, palm rejection – so you don’t accidentally hit something if your palm touches the screen – and “fuzzy hit targeting” to work out what bit of the screen you intended to poke.

It shouldn’t work, but it does: while the on-screen UI elements appear too small for touch (just like they do on Windows 7), the fuzzy targeting does a sterling job on the standard Windows controls.

For apps, however, it’s up to the developers to translate the touch data. It’ll be interesting to see how that works out.

Apple doesn’t currently make touch-screen PCs, but Lion is still touchy-feely: it works best with a trackpad such as the ones built into MacBooks or Apple’s optional Magic TrackPad, enabling you to swipe between full-screen apps, call up Mission Control to see your Spaces windows and open apps, zoom, rotate and generally fiddle around with on-screen items. The trackpad scrolling is designed to emulate iOS scrolling, which means in traditional PC terms Lion’s scrolling is upside down. You can reverse that if you wish.

TOUCHY FEELY:The Metro interface has been designed with touching and swiping, not pointing and clicking, in mind

Apps, security, performance and more

Windows 8 vs Windows 7 vs OS X Lion: handwriting and keyboards

Windows 7 and 8 both support handwriting recognition, and in Windows 8 the writing area has been expanded to make it a bit less fiddly.

Recognition is generally fine provided you keep your scribbling reasonably neat. The on-screen keyboard (on tablets) has been improved for Windows 8 too, with fuzzy hit targeting improving accuracy and a nifty thumb-based mode for fast typing when you’re holding a tablet in both hands.

WRITE STUFF:Windows’ handwriting recognition has been improved, although you still need to write reasonably neatly

Windows 8 vs Windows 7 vs OS X Lion: apps

Apple introduced an App Store in Snow Leopard, and as you’d expect it’s in Lion, too. It integrates tightly with LaunchPad, offering easy iOS-style software installation, updates and deletion. Windows 8 is getting an app store, too, although Microsoft hasn’t taken the wraps off it just yet.

Windows 8 will run two kinds of apps: traditional Windows apps, such as the Words and Excels we all know, and Metro apps, which take advantage of the new touch interface and which are sandboxed for security. That’s the case on normal PCs, anyway: ARM devices, we’re told, will run Metro apps exclusively.

Metro apps are lovely things, resembling big versions of Windows Phone apps – which, after all, is essentially what they are. We like what we’ve seen so far but it’ll be a while before it’s clear what Microsoft’s developer army comes up with.

APP HAPPY:Surprise! Apps look like apps. It’ll be interesting to see what new ideas developers come up with

Windows 8 vs Windows 7 vs OS X Lion: cloud

Windows 8 is the cloudiest version of Windows yet, and we mean that in a nice way. If you install an app from the Windows Store it’ll be available on all your PCs; enter your Windows Live account details and Windows will sync your PC settings, IE favourites, browsing history and so on, and you’ll be able to use SkyDrive to remotely access one PC from another. Apps will also be able to sync data via SkyDrive.

Apple’s approach is more mobile: iCloud is coming in iOS 5 and an imminent OS X update, delivering 5GB of free storage that you can use to sync iTunes purchases, photos, documents, contacts, calendar items and mail between your OS X and iOS devices.

If you’re a music buff, the optional iTunes Match can scan your iTunes library and stream the tracks to your Mac or iOS device. Although OS X is part of the iCloud family, it’s clear that the service is geared more towards iOS users than OS X ones.

Windows 8 vs Windows 7 vs OS X Lion: security

Windows 7 was a big step forward in terms of security, and Windows 8 takes things further. Windows 8 runs the risk of alienating anti-virus vendors, because Windows Defender now does anti-virus as well as anti-spyware – although if you install rival products Defender will let them take over. Internet Explorer has a database of known dodgy files that can help protect against malware downloads, and Metro apps are sandboxed to prevent them from accessing bits of your system they shouldn’t.

If all else fails there’s a new Clean PC option that can restore system files without harming your documents, and there’s also a reset feature that makes your PC factory-fresh without requiring a full reinstallation of Windows.

OS X reckons that user error is more of a concern than malware, and on Macs that’s probably true – despite years of dire warnings and proof of concept malware, OS X remains a virus-free environment.

Lion’s automatic saving and file versioning, as well as its superb Time Machine backup, can help avert disaster if you forget to save something, suffer a crash or accidentally damage your data. Windows 8 is expected to have a Time Machine-esque feature called File History, previously known as History Vault, that backs up libraries, contacts, favourites and the desktop to an external drive.

SAFER SOFTWARE:Windows Defender now includes anti-virus as well as anti-spyware protection

Windows 8 vs Windows 7 vs OS X Lion: performance and stability

We haven’t used finished code – that’s some way off – but initial impressions suggest that Windows 8 will run marginally faster, boot more quickly and use memory more efficiently than Windows 7 on the same hardware. Microsoft promises better battery life too, although of course we can’t test that yet.

The need for Windows to support millions of possible hardware and software combinations means it’ll inevitably crash from time to time, but from what we’ve seen so far Windows 8 should be as reliable as Windows 7 – which, in our experience, means it’ll be reasonably solid.

Apple’s tight integration of hardware and software means Lion should be more stable than Windows, but that isn’t always the case: Lion shipped with some show-stopping bugs including a video nasty that locked up entire systems at the first sniff of a video clip. Such bugs have now been squashed, however, and for us Lion has been rock solid since the last OS X update.

MEMORY MISER:Windows 8 appears to use memory more efficiently, and run faster than, Windows 7

Windows 8 vs Windows 7 vs OS X Lion: verdict

Windows 7 was really Windows Vista done properly, but the move to Windows 8 is something else entirely: it’s the biggest change in Windows since we went from Windows 3.x to Windows 95. If you currently own and like Windows 7, we think you’ll want to upgrade.

Is it better than Lion? That’s a bit like asking whether Belgium is better than spoons, or whether jazz is better than chess. The two OSes are designed to do very different things.

While Lion takes some ideas from iOS, it’s clearly a desktop-only system: there are no styluses in Apple-land, and for now at least OS X and iOS are two separate operating systems for two kinds of devices. Windows 8, on the other hand, is designed to span everything, providing a consistent experience across tablets, PCs and ultimately phones, and tying in closely with other products such as Kinect.

What we think Windows 8 has that Windows 7 perhaps didn’t is the wow factor, the iPad-y desirability that Apple fans know so well. It’s early code and it’s still evolving, but from what we’ve seen so far we’re very excited. If Microsoft pulls it off – and so far, it looks as if it might – then Windows 8 is going to be something special.